https://devblogs.microsoft.com/cppblog/msvc-cpp20-and-the-std-cpp20-switch/#c20-no_unique_address MSVC disables [[no_unique_address]] by default because of ABI compatibility. Since Abseil does not claim ABI compatibility in mixed-mode builds, we can offer it unconditionally. Fixes #1418 PiperOrigin-RevId: 518894036 Change-Id: If7653e65703b335783f11d296de7e32fc35d4fc6
